Process for producing and refining asphalt



April 27, 1954 M. H. EDSON 2,676,910

PROCESS FOR PRODUCING AND REFINING ASPHALT Filed May 26, 1951 A12. BLOWING f Zone.

FEED

T murr'ag H. Edson. sax/ember 7 Clbborrzeg DISTI LLATION 'ZQNE to obtain asphalts of desirable properties.

Patented Apr. 27, 1954 PROCESS FOR- PEQDUCI-NG AND REFINING v ASPHALT Murray H. Edison, Roselle, N. -J., assignor to Standard Oil Development Goiniiany a corporation-of Delaware Application MayZG, 1951, Serial No. 228,499

'5'Claims. -1

This invention concerns a novel process for treating residual oils and hydrocarbon residues,

The process employed depends upon a heat treatment of the residual oil in the presence of P205. This process can in many cases be advantageously varied by air blowing the residual oil prior to contact with P205, or by air blowing the asphalt obtained by treatment of residual oil with P205. While as indicated, the process is particularly adapted for the treatment of residual oils to recover asphalts therefrom; the process may also be'employed tor the upgrading of asphalts obtained by conventional processing steps.

The present invention concerns the recovery of as'phalts'and the refining of asphalts obtained from petroleum oils. The principal objective of the process herein disclosed is to provide asphalts having unusual properties; in particular, asphalts are obtained which have usually high penetration and ductility properties for a given softening point, although, as will be brought out, other desirable properties may also be realized. This unusual combination of characteristics is demanded in a number of applicationsan out standing example of which is the lining of irrigationcanals. Asphalts employed to line irrigation canals ideally "should have properties to enable the asphalt lining to retain its shape in hot weathento be non-brittle incold weather, and to conform to the contour of the surface of the canal without tearing. Asphalts having these properties must have a softening point of about 175 to 200 F., and must have high ductility and high values of penetration. It has been found that asphalts obtained by conventional processihg methods do not have the necessary combination of properties. More preciselyythe asphalts obtained by conventional processing techniques, in the-range of softening points identified, have too low a ductility and too low 'a enetrauonto meet the desired characteristics.

It is therefore the principal object or this invention to provide an asphalt recovery and treating process which will vary the usual combination of softening point,- penetration, and ductility properties. To bring out themanner in which these asphalt properties are affected, it is helpful to consider the results of subjecting crude residua to an oxidation treatment as achieved by conventional air blowing. Oxidation treatments of this character are well known to the art and it has been appreciated that the low temperature susceptibility of asphalts may to some extent be improved by oxidation. However, when air blowing is applied and continued, while the softening point of an asphalt is raised,

the penetration is decreased and the ductility is 2 lowered. Consequently, contrato this change in asphalt "propertieathe process of this invention provides an increase in penetration properties and an increase in ductility concomitant with the increase in softening point of the asphalt.

The process by which these desirable changes in asphalt properties are obtained depends upon the catalytic treatment of residual oils or 'asphalts with P205. The precise mechanism of the asphalt change which occurs is not understood, although the principal effect appears to depend upon polymerization and condensation reactions. It is important to note that the treatment is in no respect an oxidation treatment, and in fact 'oxidation'or the presence of air during the'process is to be avoided. Thus, it has been determined that for the purposes of this invention, degradation in asphalt quality results from the presence of air during treatment with thePzOs.

The quantity of P205 to be employed ranges from about 0:1 to- 5% by weight. The precise amount of P205 to be used depends principally upon the properties desired and'the starting materials. In all cases treatment with P205 is preferably continued until equilibrium has been obtained. As the P205 treatment of asphalt proce'eds readily, the time required is reasonably short anduoes not ordinarily exceed one hour. The temperature of treatment with P205 is chosen from the range of 300 to 550 F. Again, the precise temperature to'be used depends to some extent u on the asphalt characteristics desired and the starting materials.

This treatment of a residual oil or an asphalt with P205 atBGG" to 550 F. in the absence of air or'oxygen produces a material change in the properties of the asphalt. In particular, the softening point of the asphalt is raised and the temperature susceptibility of the asphalt is improved to values otherwise unobtainable.

While as indicated, the critical treatment with P205 depends upon the exclusion of any oxidation ei fect's, it ha's been found valuable in'certain applications to em loy an oxidation treatment eitherbefore or after, but not simultaneously with the P205 treatment. One adaptation or the process of this invention therefore depends upon oxidizing an asphalt followed with P205 treatment in the absence of air; another adapta than of the process utilizes P205 treatment in the absence of air followed by an oxidation treatmerit. Both'o'f these'adaptations causes a variation'in'asphalt properties different from those which occur without the oxidation treatment or when the oxidation'is applied simultaneously with the P293 treatment. Furthermore, the

- oxidation treatment wheni'applied before or after the P205 treatment, decreases the amount of P205 required to attain a particular softening point.

To fully disclose the nature of this invention, reference will be made to the accompanying drawing which diagrammatically illustrates a flow plan of a preferred process embodying this invention. The process illustrated in the drawing concerns the preparation of asphalt from a residual oil obtained by distillation of a crude petroleum oil, although it is to be understood that the process illustrated may be applied to asphalts which may be obtained by other methods. The term residual oils by definition is employed to identify the liquid or semi-solid residues obtained from the destructive distillation of non-asphaltic petroleum, from the distillation of semi-asphaltic and asphaltic petroleums, from the distillation of pressure tar, or from the iiuxing of harder residual asphalts with heavy distillates. The term flux or flux oil may be used synonymously with the term residual oil.

By way of example, in the process illustrated in the drawing, a residual oil is obtained in distillation zone I by treatment of a semi-asphaltie or asphaltic petroleum oil introduced to still I through line 2. Normally gaseous hydrocarbons may be withdrawn from distillation zone I through line 3, while side stream products consisting of gasoline, kerosene, gas oil, lubricating oil, etc., may be withdrawn through lines 4, 5, 6, etc. The residual oil may be removed as the bottoms produce from the distillation zone through line I and will include substantially all of the asphaltic constituents originally present in the crude oil distilled. The specific gravity of the residual oil at 77 F. will range from about 0.85 to 1.07, and the fusing point of the oil as determined by the ring and ball method will generally fall within the range of 32 to 120 F. This residual oil may be converted to an asphalt of desirable properties by the processing sequence illustrated in the drawing.

As will be brought out, the primary and essential treatment of the residual oil depends upon a catalytic treatment with P205 in refining zone I0. Use of the two air blowing zones II and I2 is optional and for simplicity it may be assumed that zones II and I2 are by-passed by the by-pass lines provided. In this case the residual oil withdrawn from distillation zone I through line I will preferably be passed through a pre-heater I3 and will then be introduced directly into refining zone I0. Sufficient P205 is introduced to zone I through line I 4 to provide a weight percent of about 0.1 to 5%. Mechanical agitation by inert gases such as nitrogen is employed in zone III to thoroughly mix the residual oil and P205. By suitably preheating the residual oil in preheater I3 and/or by utilizing heatin jackets, steam coils, etc., in zone I0, mixing in zone I0 is carried out at a temperature in the range of 300 to 550 F. Care is taken to exclude air or oxygen from zone I0. As a result, with this treatment of P205, the softening point of the asphalt is increased and other properties of the asphalt are changed. The ultimate properties obtainable are dependent upon the particular temperature of treatment, the percentage of P205 employed, and the initial flux oil treated. Prior to reaching equilibrium properties, the time of treatment will also affect the asphalt properties. However, it is important to continue the mixing until no further change in properties occurs, This can be readily determined by periodically determining the softening point, the penetration or other inspections of the asphalt during treatment. In general, about 30 to minutes are to be employed for the P205 treatment, depending upon starting material, temperature, quantity of change, amount of P205, and degree of agitation. The final asphalt product may then be removed from zone I0 through line I5.

As will be demonstrated, in some cases it is preferred to air blow the residual oil or asphalt prior to the P205 treatment. In this case the residual oil of line I is introduced to zone I I for contact with an oxidation agent such as air. The oxidation treatment may be conducted in any desired manner; for example, by blowing about 30 to 50 cu. ft. of air per minute per ton of asphalt through the residual oil at about 300 to 550 F. temperature. Thereafter the air blown oil may be withdrawn from zone II and passed through preheater I3 for treatment with P205 in zone III as described. The final asphalt product is then obtained by withdrawing the asphalt directly from zone I0 through line I5.

Rather than applying the oxidation treatment prior to P205 treatment, it is sometimes preferred to apply the oxidation treatment after the P205 treatment. In this case the residual oil of line I will by-pass zone II and will be subjected to P205 treatment in zone I0. Thereafter the asphalt removed from zone I0 through line I5 will be passed to oxidation zone I2 wherein a treatment similar to that applied in oxidation zone II will be employed. In this case the final asphalt product will be withdrawn from line II.

To exemplify the operability and utility of the process described, the following examples are presented, showing the properties of asphalts obtainable.

EXAMPLE I As typical of the asphalts obtained by the conventional reduction of residual oils a Venezuelan crude oil was subjected to vacuum reduction providing an asphalt of the following properties:

Table I.Vacuum reduced asphalt Flash point (Cleveland open cup) After an oxidation treatment as provided by air blowing, an asphalt of the character identified in Table I has the following typical properties provided by different degrees of oxidation A, B and C.

Table II.-Oa:idized reduced asphalt Flash Point (Cleveland Ogien Cup), F 530 510 585 Sofenting Point (Ring an Ball), F 195 226 291 Penetration at 77 F./l00 gms./5 sec 29 16 5 Penetration at 32 R1200 gIHSJfiO sec. 18 ll 2 Penetration at F./50 gms./5 sec 45 31 6 Ductility at 77 F., em 3. 5 2. 5 0 P. T. S.Xl00 1.22 .l. l4 1.13

1 Penetration temperature suseeptlbility= log SOD-log pen. at 77 F.

softening point (F.) 77

As indicated by this-= example, asphalts obtained. by: theaoxidation .-'of-'.residua'l 'oi'lsare characterized .by. hightemperature. susceptibility. The asphalts arerelatively brittle, possess poor ductility. and are otherwise unsuitable for application such as the. lining of irrigation canals.

' The residual oil identified in Table I was sub jected to P2O5treatment in the absence of air at a temperature of 450 F. Various quantities of P205, reported in weight percent, were employed. The residual oil and'P205 were stirredin a closed vessel, while passing a flow of nitrogen through the mixture to .completely. excludethe presence of air. Theresulting asphalt possessed the following. properties:

Table III.'.Residu'aloil-P205 treated" absencev of'oxygen Penetration at 77 F./l gms1/5 sec Penetration at 32 ./200 gms./60 sec Penetration at 115 F-./50 gins/ sec Ductility at 77 F., cm 4 Penetration TemperatureSusceptibility X l00 .978 .787' .673

In considering this data, it is significant that the P205 treatment in the absence of oxygen resulted in an increase'in the softening'point of the asphalt in proportion to the amount of- P205 employed. To'this extent: the treatment has a similar effect to oxidation as illustrated by Table II. However, unlike oxidation, the P205 treatment provides asphalts of lower temperature susceptibility and greater ductility at comparable softening points. This is-well demonstrated by a comparison of Table'II" and Table III, showing the properties of three asphalts of approximately the same-softening point as-obtained by oxidation and P205 treatment respectively.

To further illustrate the efiec-t-ofreacting P205 in .the absence. of air other dataemploying asphalts and blended asphalts'irom other crude sources were obtained'z" Table'IV Talco Blend Talco Blend Vacuum ;oi.21'/30.Pen. of 2l/30Pen. Reduced Straight Straight Talco Reduced Reduced Crude, 110 Asphalt Asphalt S. P., with Phenol with Phenol 1,156 Furol Extract, Extract, 836 Vis. Sec. at 1,079 Furol Furol Vis.

210 F. Vis. sec. at Sec. at 210 Percent P205 l. 2 2% 2% Flash (Cleveland Open Cup), F 525 530 S. P. (Ring and Ball),

F 174 187 205 Pen., 77 F./l00 gms./5

sec 47 57 53 Pen., 32 F./200gms./60

sec 29 32 31 Pen., 115 F./50 gins/5 In the data shown, the blended asphalts were prepared by utilizing the phenol extract of lubricating oil to provide asphalts of the indicated properties. These data reveal that crude source, composition, viscosity, etc., may influence, but do not prevent the reaction of P205 in the absence of air with the asphalt. The properties shown above indicate that the catalytically prepared 6": asphalts have lower temperature susceptibility, arev more ductile and are better. than. those that may. be. produced by blending. or. vacuum reduction.

EXAMPLE III As indicated, the treatment of a residual oil or an asphalt with P205 in accordance with this invention,. provides asphalts having properties not. obtainable by an oxidation treatment. To obtain'the full benefits of this invention there: fore, P205 treatment must be conducted seas. to exclude air to eliminate" oxidation eiiects occurring. simultaneously with the P205 treatment. The deleterious effects caused by the presence of oxygen while treating with P205 are shown. .by the following: data:

"Table V.-Talco flux 110 F. S. P; 1155 'Furol Vis. at 210 F.

N 0 Air Present Air Present Percent P205 0.7 1.94 0.7 l. 96

S. P. (Ring and Ball), "F 130 Pen., 77 F./10O gins/5 scc 80 Pen., 32 F./200 gins/60 sec 28 Duct., 77 F., cm 67 P. T. S.) l00 1.89 1.

EXAMPLE IV As demonstrated, oxidation during P205-treatment is to be avoided to prevent degradation in the properties of the asphalt obtained. However, carefully controlled and relatively mild oxidation may in some cases advantageously be employed prior to the P205. treatment. This per"- mits a reduction in the amount of P205 required to obtain an asphalt of a particular softening point, while still providing an asphalt. of substantially the. same quality. The asphalt ob.- tained is superior to asphalt producedb oxidation alone or produced by P205 treatment; conducted. in the presence of air. This processuis particularly adapted for. improving. the properties of. an asphalt which has been. oxidized.

These principles are illustrated in Table VI below, showing the effect of P205 treating an asphalt, in the absence of oxygen, after submitting the asphalt to a prior oxidation treatment conducted so as to only partially raise the softening point toward the desired value. The air blowing or oxidation treatment employed consisted of passing 30.5 cu. ft. of air/minute/ton through the asphalt for two hours at 450 F. The subsequent P205 treatment employed 1%; weight percent P205.

Table VI.--O.1:idation followed by P205 treatment P2 0 5 Treatment of Air Blown Flux Vene- Air zuelan Flux EXAMPLE V It is sometimes desirable to utilize an oxidation treatment as a finishing step after a prior P205 treatment conducted in the absence of oxygen. This permits an increase in the softening point of the P205 treated asphalt without causing any substantial degradation in the other properties of the asphalt. Again this process permits obtaining an asphalt of a desired softening point and other properties while minimizing the quantity of P205 required.

Table VII shows the properties of an asphalt which was subjected to oxidation treatment after a P205 treat in the absence of oxygen. The initial feed material was a Venezuelan flux which was raised to a softening point of 232 F. by treatment with P205 in the absence of oxygen. Thereafter this asphalt was oxidized to a final softening point of 250 F. The inspections of this asphalt were as follows:

Table VIL-Cmidation of P205 treated asphalt Flash (Cleveland open cup) F 540 Softening point (ring and ball) F 250 Penetration at 77 F./100 gms./ sec 42 Penetration at 32 F./200 gins/60 sec 29 Penetration at 115 F./50 gms./5 sec 60 Ductility at 77 F., cm 2 P. T, S. X l00 0.74

The relatively high ductility and low temperature susceptibility of this high softening point asphalt are significant.

EXAMPLE VI As brought out by the preceding examples, asphalts of desired properties are obtained by a P205 treatment in the absence of air. In particular such asphalts ar noted by high softening point, low temperature susceptibility, and high ductility. However, other properties of these asphalts are notable. For example, it has been found that cut-back asphalts prepared by dilution of an asphalt with an agent such as naphtha are resistant to gellation. Gelling of an asphalt is notable on storage, causing a substantial increase in the viscosity of the asphalt, making use of the asphalt difiicult or impossible. The gelling properties of an asphalt prepared by air blowing a Venezuelan stock and by P205 treating this stock are shown in the following table:

,8 Table VIII CUTBACK ASPHALT-VISCOSITY INCREASE [45% asphalt by weight; naptha by weight] 210 S. P. Venezuelan Stock Prepared by P205 Treatment of Venezuelan Flux; Pen. at 32 F.=39

220/235 Venezuelan Stock Prepared by air blowing; Pen. at 32 F.=l1

1 day 60,000+ cps.; gelled immediatel 31 cps. 4 days 34 cps. 11 days. 37 cps. 13 days 41 cps. 19 days 44 cps.

The P205 treated asphalt was prepared by treating the identified flux with 2.2 wt. percent of P205 with agitation in the absence of air for 5 hours at 450 F. As shown by this data, the P205 treated asphalt was not subject to gellation.

What is claimed is:

1. A process for treating residual oils comprising adding about 0.1 to 5% by weight of P205 to said residual oil and agitating said mixture in the absence of free oxygen at a temperature of about 300 to 550 F.

2. In the treatment of residual oils and asphalts with P205, the improvement which comprises adding about 0.1 to 5 weight percent of P205 to the said composition to be treated and thereafter agitating this mixture in the absence of free oxygen at a temperature of about 300 to 550 F.

3. A process for producing asphalt from a residual oil in which the residual oil is mixed with about 0.1 to 5 weight percent of P205 in the absence of free oxygen at a temperature of about 300 to 550 F.

4. The process defined by claim 3 in which the said residual oil is oxidized prior to the said treatment with P205.

5. The process defined by claim 3 in which the said treated mixture is oxidized after the said treatment with P205.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,179,208 Burk et a1 Nov. 7, 1939 2,281,728 Thelen May 5, 1942 2,450,756 Hoiberg Oct. 5, 1948 

1. A PROCESS FOR TREATING RESIDUALS OILS COMPRISING ADDING ABOUT 0.1 TO 5% BY WEIGHT OF P205 TO SAID RESIDUAL OIL AND AGITATING SAID MIXTURE IN 